As a conventional technique, a system for tracking a moving object is disclosed. As to this system, in time sequence images, a plurality of moving objects is detected from a plurality of frames included therein. By corresponding the same object among the frames, the moving object is tracked. This tracking result is recorded. Based on the tracking result, the moving object is discriminated.
Furthermore, in this system, a person's face is detected from the time series images. Specifically, appearance and disappearance of the face are detected therefrom. By setting appearance of the face, disappearance of the face, and failure of detection of the face to each node, a combination of branches (path) having nodes is examined. Here, the plurality of moving objects is complicatedly moving in the time series images. Accordingly, a cost to calculate the combination of branches greatly increases.